Merge tag 'ecryptfs-3.18-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git...
[muen/linux.git] / fs / ecryptfs / inode.c
1 /**
2  * eCryptfs: Linux filesystem encryption layer
3  *
4  * Copyright (C) 1997-2004 Erez Zadok
5  * Copyright (C) 2001-2004 Stony Brook University
6  * Copyright (C) 2004-2007 International Business Machines Corp.
7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation; either version 2 of the
13  * License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23  * 02111-1307, USA.
24  */
25
26 #include <linux/file.h>
27 #include <linux/vmalloc.h>
28 #include <linux/pagemap.h>
29 #include <linux/dcache.h>
30 #include <linux/namei.h>
31 #include <linux/mount.h>
32 #include <linux/crypto.h>
33 #include <linux/fs_stack.h>
34 #include <linux/slab.h>
35 #include <linux/xattr.h>
36 #include <asm/unaligned.h>
37 #include "ecryptfs_kernel.h"
38
39 static struct dentry *lock_parent(struct dentry *dentry)
40 {
41         struct dentry *dir;
42
43         dir = dget_parent(dentry);
44         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
45         return dir;
46 }
47
48 static void unlock_dir(struct dentry *dir)
49 {
50         mutex_unlock(&dir->d_inode->i_mutex);
51         dput(dir);
52 }
53
54 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
55 {
56         return ecryptfs_inode_to_lower(inode) == lower_inode;
57 }
58
59 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
60 {
61         struct inode *lower_inode = opaque;
62
63         ecryptfs_set_inode_lower(inode, lower_inode);
64         fsstack_copy_attr_all(inode, lower_inode);
65         /* i_size will be overwritten for encrypted regular files */
66         fsstack_copy_inode_size(inode, lower_inode);
67         inode->i_ino = lower_inode->i_ino;
68         inode->i_version++;
69         inode->i_mapping->a_ops = &ecryptfs_aops;
70         inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
71
72         if (S_ISLNK(inode->i_mode))
73                 inode->i_op = &ecryptfs_symlink_iops;
74         else if (S_ISDIR(inode->i_mode))
75                 inode->i_op = &ecryptfs_dir_iops;
76         else
77                 inode->i_op = &ecryptfs_main_iops;
78
79         if (S_ISDIR(inode->i_mode))
80                 inode->i_fop = &ecryptfs_dir_fops;
81         else if (special_file(inode->i_mode))
82                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
83         else
84                 inode->i_fop = &ecryptfs_main_fops;
85
86         return 0;
87 }
88
89 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
90                                           struct super_block *sb)
91 {
92         struct inode *inode;
93
94         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
95                 return ERR_PTR(-EXDEV);
96         if (!igrab(lower_inode))
97                 return ERR_PTR(-ESTALE);
98         inode = iget5_locked(sb, (unsigned long)lower_inode,
99                              ecryptfs_inode_test, ecryptfs_inode_set,
100                              lower_inode);
101         if (!inode) {
102                 iput(lower_inode);
103                 return ERR_PTR(-EACCES);
104         }
105         if (!(inode->i_state & I_NEW))
106                 iput(lower_inode);
107
108         return inode;
109 }
110
111 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
112                                  struct super_block *sb)
113 {
114         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
115
116         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
117                 unlock_new_inode(inode);
118
119         return inode;
120 }
121
122 /**
123  * ecryptfs_interpose
124  * @lower_dentry: Existing dentry in the lower filesystem
125  * @dentry: ecryptfs' dentry
126  * @sb: ecryptfs's super_block
127  *
128  * Interposes upper and lower dentries.
129  *
130  * Returns zero on success; non-zero otherwise
131  */
132 static int ecryptfs_interpose(struct dentry *lower_dentry,
133                               struct dentry *dentry, struct super_block *sb)
134 {
135         struct inode *inode = ecryptfs_get_inode(lower_dentry->d_inode, sb);
136
137         if (IS_ERR(inode))
138                 return PTR_ERR(inode);
139         d_instantiate(dentry, inode);
140
141         return 0;
142 }
143
144 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
145                               struct inode *inode)
146 {
147         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
148         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
149         struct dentry *lower_dir_dentry;
150         int rc;
151
152         dget(lower_dentry);
153         lower_dir_dentry = lock_parent(lower_dentry);
154         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
155         if (rc) {
156                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
157                 goto out_unlock;
158         }
159         fsstack_copy_attr_times(dir, lower_dir_inode);
160         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
161         inode->i_ctime = dir->i_ctime;
162         d_drop(dentry);
163 out_unlock:
164         unlock_dir(lower_dir_dentry);
165         dput(lower_dentry);
166         return rc;
167 }
168
169 /**
170  * ecryptfs_do_create
171  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
172  * @ecryptfs_dentry: New file's dentry in ecryptfs
173  * @mode: The mode of the new file
174  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
175  *
176  * Creates the underlying file and the eCryptfs inode which will link to
177  * it. It will also update the eCryptfs directory inode to mimic the
178  * stat of the lower directory inode.
179  *
180  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
181  */
182 static struct inode *
183 ecryptfs_do_create(struct inode *directory_inode,
184                    struct dentry *ecryptfs_dentry, umode_t mode)
185 {
186         int rc;
187         struct dentry *lower_dentry;
188         struct dentry *lower_dir_dentry;
189         struct inode *inode;
190
191         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
192         lower_dir_dentry = lock_parent(lower_dentry);
193         rc = vfs_create(lower_dir_dentry->d_inode, lower_dentry, mode, true);
194         if (rc) {
195                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
196                        "rc = [%d]\n", __func__, rc);
197                 inode = ERR_PTR(rc);
198                 goto out_lock;
199         }
200         inode = __ecryptfs_get_inode(lower_dentry->d_inode,
201                                      directory_inode->i_sb);
202         if (IS_ERR(inode)) {
203                 vfs_unlink(lower_dir_dentry->d_inode, lower_dentry, NULL);
204                 goto out_lock;
205         }
206         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
207         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
208 out_lock:
209         unlock_dir(lower_dir_dentry);
210         return inode;
211 }
212
213 /**
214  * ecryptfs_initialize_file
215  *
216  * Cause the file to be changed from a basic empty file to an ecryptfs
217  * file with a header and first data page.
218  *
219  * Returns zero on success
220  */
221 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
222                              struct inode *ecryptfs_inode)
223 {
224         struct ecryptfs_crypt_stat *crypt_stat =
225                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
226         int rc = 0;
227
228         if (S_ISDIR(ecryptfs_inode->i_mode)) {
229                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
230                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
231                 goto out;
232         }
233         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
234         rc = ecryptfs_new_file_context(ecryptfs_inode);
235         if (rc) {
236                 ecryptfs_printk(KERN_ERR, "Error creating new file "
237                                 "context; rc = [%d]\n", rc);
238                 goto out;
239         }
240         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
241         if (rc) {
242                 printk(KERN_ERR "%s: Error attempting to initialize "
243                         "the lower file for the dentry with name "
244                         "[%pd]; rc = [%d]\n", __func__,
245                         ecryptfs_dentry, rc);
246                 goto out;
247         }
248         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
249         if (rc)
250                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
251         ecryptfs_put_lower_file(ecryptfs_inode);
252 out:
253         return rc;
254 }
255
256 /**
257  * ecryptfs_create
258  * @dir: The inode of the directory in which to create the file.
259  * @dentry: The eCryptfs dentry
260  * @mode: The mode of the new file.
261  *
262  * Creates a new file.
263  *
264  * Returns zero on success; non-zero on error condition
265  */
266 static int
267 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
268                 umode_t mode, bool excl)
269 {
270         struct inode *ecryptfs_inode;
271         int rc;
272
273         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
274                                             mode);
275         if (unlikely(IS_ERR(ecryptfs_inode))) {
276                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
277                                 "lower filesystem\n");
278                 rc = PTR_ERR(ecryptfs_inode);
279                 goto out;
280         }
281         /* At this point, a file exists on "disk"; we need to make sure
282          * that this on disk file is prepared to be an ecryptfs file */
283         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
284         if (rc) {
285                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
286                                    ecryptfs_inode);
287                 make_bad_inode(ecryptfs_inode);
288                 unlock_new_inode(ecryptfs_inode);
289                 iput(ecryptfs_inode);
290                 goto out;
291         }
292         unlock_new_inode(ecryptfs_inode);
293         d_instantiate(ecryptfs_dentry, ecryptfs_inode);
294 out:
295         return rc;
296 }
297
298 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
299 {
300         struct ecryptfs_crypt_stat *crypt_stat;
301         int rc;
302
303         rc = ecryptfs_get_lower_file(dentry, inode);
304         if (rc) {
305                 printk(KERN_ERR "%s: Error attempting to initialize "
306                         "the lower file for the dentry with name "
307                         "[%pd]; rc = [%d]\n", __func__,
308                         dentry, rc);
309                 return rc;
310         }
311
312         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
313         /* TODO: lock for crypt_stat comparison */
314         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
315                 ecryptfs_set_default_sizes(crypt_stat);
316
317         rc = ecryptfs_read_and_validate_header_region(inode);
318         ecryptfs_put_lower_file(inode);
319         if (rc) {
320                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
321                 if (!rc)
322                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
323         }
324
325         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
326         return 0;
327 }
328
329 /**
330  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
331  */
332 static int ecryptfs_lookup_interpose(struct dentry *dentry,
333                                      struct dentry *lower_dentry,
334                                      struct inode *dir_inode)
335 {
336         struct inode *inode, *lower_inode = lower_dentry->d_inode;
337         struct ecryptfs_dentry_info *dentry_info;
338         struct vfsmount *lower_mnt;
339         int rc = 0;
340
341         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
342         if (!dentry_info) {
343                 printk(KERN_ERR "%s: Out of memory whilst attempting "
344                        "to allocate ecryptfs_dentry_info struct\n",
345                         __func__);
346                 dput(lower_dentry);
347                 return -ENOMEM;
348         }
349
350         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
351         fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
352         BUG_ON(!d_count(lower_dentry));
353
354         ecryptfs_set_dentry_private(dentry, dentry_info);
355         dentry_info->lower_path.mnt = lower_mnt;
356         dentry_info->lower_path.dentry = lower_dentry;
357
358         if (!lower_dentry->d_inode) {
359                 /* We want to add because we couldn't find in lower */
360                 d_add(dentry, NULL);
361                 return 0;
362         }
363         inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
364         if (IS_ERR(inode)) {
365                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
366                        __func__, PTR_ERR(inode));
367                 return PTR_ERR(inode);
368         }
369         if (S_ISREG(inode->i_mode)) {
370                 rc = ecryptfs_i_size_read(dentry, inode);
371                 if (rc) {
372                         make_bad_inode(inode);
373                         return rc;
374                 }
375         }
376
377         if (inode->i_state & I_NEW)
378                 unlock_new_inode(inode);
379         d_add(dentry, inode);
380
381         return rc;
382 }
383
384 /**
385  * ecryptfs_lookup
386  * @ecryptfs_dir_inode: The eCryptfs directory inode
387  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
388  * @ecryptfs_nd: nameidata; may be NULL
389  *
390  * Find a file on disk. If the file does not exist, then we'll add it to the
391  * dentry cache and continue on to read it from the disk.
392  */
393 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
394                                       struct dentry *ecryptfs_dentry,
395                                       unsigned int flags)
396 {
397         char *encrypted_and_encoded_name = NULL;
398         size_t encrypted_and_encoded_name_size;
399         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
400         struct dentry *lower_dir_dentry, *lower_dentry;
401         int rc = 0;
402
403         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
404         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
405         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
406                                       lower_dir_dentry,
407                                       ecryptfs_dentry->d_name.len);
408         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
409         if (IS_ERR(lower_dentry)) {
410                 rc = PTR_ERR(lower_dentry);
411                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
412                                 "[%d] on lower_dentry = [%pd]\n", __func__, rc,
413                                 ecryptfs_dentry);
414                 goto out;
415         }
416         if (lower_dentry->d_inode)
417                 goto interpose;
418         mount_crypt_stat = &ecryptfs_superblock_to_private(
419                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
420         if (!(mount_crypt_stat
421             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
422                 goto interpose;
423         dput(lower_dentry);
424         rc = ecryptfs_encrypt_and_encode_filename(
425                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
426                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
427                 ecryptfs_dentry->d_name.len);
428         if (rc) {
429                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
430                        "filename; rc = [%d]\n", __func__, rc);
431                 goto out;
432         }
433         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
434         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
435                                       lower_dir_dentry,
436                                       encrypted_and_encoded_name_size);
437         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
438         if (IS_ERR(lower_dentry)) {
439                 rc = PTR_ERR(lower_dentry);
440                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
441                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
442                                 encrypted_and_encoded_name);
443                 goto out;
444         }
445 interpose:
446         rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
447                                        ecryptfs_dir_inode);
448 out:
449         kfree(encrypted_and_encoded_name);
450         return ERR_PTR(rc);
451 }
452
453 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
454                          struct dentry *new_dentry)
455 {
456         struct dentry *lower_old_dentry;
457         struct dentry *lower_new_dentry;
458         struct dentry *lower_dir_dentry;
459         u64 file_size_save;
460         int rc;
461
462         file_size_save = i_size_read(old_dentry->d_inode);
463         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
464         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
465         dget(lower_old_dentry);
466         dget(lower_new_dentry);
467         lower_dir_dentry = lock_parent(lower_new_dentry);
468         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
469                       lower_new_dentry, NULL);
470         if (rc || !lower_new_dentry->d_inode)
471                 goto out_lock;
472         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
473         if (rc)
474                 goto out_lock;
475         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
476         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
477         set_nlink(old_dentry->d_inode,
478                   ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink);
479         i_size_write(new_dentry->d_inode, file_size_save);
480 out_lock:
481         unlock_dir(lower_dir_dentry);
482         dput(lower_new_dentry);
483         dput(lower_old_dentry);
484         return rc;
485 }
486
487 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
488 {
489         return ecryptfs_do_unlink(dir, dentry, dentry->d_inode);
490 }
491
492 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
493                             const char *symname)
494 {
495         int rc;
496         struct dentry *lower_dentry;
497         struct dentry *lower_dir_dentry;
498         char *encoded_symname;
499         size_t encoded_symlen;
500         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
501
502         lower_dentry = ecryptfs_dentry_to_lower(dentry);
503         dget(lower_dentry);
504         lower_dir_dentry = lock_parent(lower_dentry);
505         mount_crypt_stat = &ecryptfs_superblock_to_private(
506                 dir->i_sb)->mount_crypt_stat;
507         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
508                                                   &encoded_symlen,
509                                                   NULL,
510                                                   mount_crypt_stat, symname,
511                                                   strlen(symname));
512         if (rc)
513                 goto out_lock;
514         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
515                          encoded_symname);
516         kfree(encoded_symname);
517         if (rc || !lower_dentry->d_inode)
518                 goto out_lock;
519         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
520         if (rc)
521                 goto out_lock;
522         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
523         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
524 out_lock:
525         unlock_dir(lower_dir_dentry);
526         dput(lower_dentry);
527         if (!dentry->d_inode)
528                 d_drop(dentry);
529         return rc;
530 }
531
532 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
533 {
534         int rc;
535         struct dentry *lower_dentry;
536         struct dentry *lower_dir_dentry;
537
538         lower_dentry = ecryptfs_dentry_to_lower(dentry);
539         lower_dir_dentry = lock_parent(lower_dentry);
540         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
541         if (rc || !lower_dentry->d_inode)
542                 goto out;
543         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
544         if (rc)
545                 goto out;
546         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
547         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
548         set_nlink(dir, lower_dir_dentry->d_inode->i_nlink);
549 out:
550         unlock_dir(lower_dir_dentry);
551         if (!dentry->d_inode)
552                 d_drop(dentry);
553         return rc;
554 }
555
556 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
557 {
558         struct dentry *lower_dentry;
559         struct dentry *lower_dir_dentry;
560         int rc;
561
562         lower_dentry = ecryptfs_dentry_to_lower(dentry);
563         dget(dentry);
564         lower_dir_dentry = lock_parent(lower_dentry);
565         dget(lower_dentry);
566         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
567         dput(lower_dentry);
568         if (!rc && dentry->d_inode)
569                 clear_nlink(dentry->d_inode);
570         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
571         set_nlink(dir, lower_dir_dentry->d_inode->i_nlink);
572         unlock_dir(lower_dir_dentry);
573         if (!rc)
574                 d_drop(dentry);
575         dput(dentry);
576         return rc;
577 }
578
579 static int
580 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
581 {
582         int rc;
583         struct dentry *lower_dentry;
584         struct dentry *lower_dir_dentry;
585
586         lower_dentry = ecryptfs_dentry_to_lower(dentry);
587         lower_dir_dentry = lock_parent(lower_dentry);
588         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
589         if (rc || !lower_dentry->d_inode)
590                 goto out;
591         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
592         if (rc)
593                 goto out;
594         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
595         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
596 out:
597         unlock_dir(lower_dir_dentry);
598         if (!dentry->d_inode)
599                 d_drop(dentry);
600         return rc;
601 }
602
603 static int
604 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
605                 struct inode *new_dir, struct dentry *new_dentry)
606 {
607         int rc;
608         struct dentry *lower_old_dentry;
609         struct dentry *lower_new_dentry;
610         struct dentry *lower_old_dir_dentry;
611         struct dentry *lower_new_dir_dentry;
612         struct dentry *trap = NULL;
613         struct inode *target_inode;
614
615         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
616         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
617         dget(lower_old_dentry);
618         dget(lower_new_dentry);
619         lower_old_dir_dentry = dget_parent(lower_old_dentry);
620         lower_new_dir_dentry = dget_parent(lower_new_dentry);
621         target_inode = new_dentry->d_inode;
622         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
623         /* source should not be ancestor of target */
624         if (trap == lower_old_dentry) {
625                 rc = -EINVAL;
626                 goto out_lock;
627         }
628         /* target should not be ancestor of source */
629         if (trap == lower_new_dentry) {
630                 rc = -ENOTEMPTY;
631                 goto out_lock;
632         }
633         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
634                         lower_new_dir_dentry->d_inode, lower_new_dentry,
635                         NULL, 0);
636         if (rc)
637                 goto out_lock;
638         if (target_inode)
639                 fsstack_copy_attr_all(target_inode,
640                                       ecryptfs_inode_to_lower(target_inode));
641         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
642         if (new_dir != old_dir)
643                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
644 out_lock:
645         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
646         dput(lower_new_dir_dentry);
647         dput(lower_old_dir_dentry);
648         dput(lower_new_dentry);
649         dput(lower_old_dentry);
650         return rc;
651 }
652
653 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
654 {
655         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
656         char *lower_buf;
657         char *buf;
658         mm_segment_t old_fs;
659         int rc;
660
661         lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
662         if (!lower_buf)
663                 return ERR_PTR(-ENOMEM);
664         old_fs = get_fs();
665         set_fs(get_ds());
666         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
667                                                    (char __user *)lower_buf,
668                                                    PATH_MAX);
669         set_fs(old_fs);
670         if (rc < 0)
671                 goto out;
672         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
673                                                   lower_buf, rc);
674 out:
675         kfree(lower_buf);
676         return rc ? ERR_PTR(rc) : buf;
677 }
678
679 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
680 {
681         size_t len;
682         char *buf = ecryptfs_readlink_lower(dentry, &len);
683         if (IS_ERR(buf))
684                 goto out;
685         fsstack_copy_attr_atime(dentry->d_inode,
686                                 ecryptfs_dentry_to_lower(dentry)->d_inode);
687         buf[len] = '\0';
688 out:
689         nd_set_link(nd, buf);
690         return NULL;
691 }
692
693 /**
694  * upper_size_to_lower_size
695  * @crypt_stat: Crypt_stat associated with file
696  * @upper_size: Size of the upper file
697  *
698  * Calculate the required size of the lower file based on the
699  * specified size of the upper file. This calculation is based on the
700  * number of headers in the underlying file and the extent size.
701  *
702  * Returns Calculated size of the lower file.
703  */
704 static loff_t
705 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
706                          loff_t upper_size)
707 {
708         loff_t lower_size;
709
710         lower_size = ecryptfs_lower_header_size(crypt_stat);
711         if (upper_size != 0) {
712                 loff_t num_extents;
713
714                 num_extents = upper_size >> crypt_stat->extent_shift;
715                 if (upper_size & ~crypt_stat->extent_mask)
716                         num_extents++;
717                 lower_size += (num_extents * crypt_stat->extent_size);
718         }
719         return lower_size;
720 }
721
722 /**
723  * truncate_upper
724  * @dentry: The ecryptfs layer dentry
725  * @ia: Address of the ecryptfs inode's attributes
726  * @lower_ia: Address of the lower inode's attributes
727  *
728  * Function to handle truncations modifying the size of the file. Note
729  * that the file sizes are interpolated. When expanding, we are simply
730  * writing strings of 0's out. When truncating, we truncate the upper
731  * inode and update the lower_ia according to the page index
732  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
733  * the caller must use lower_ia in a call to notify_change() to perform
734  * the truncation of the lower inode.
735  *
736  * Returns zero on success; non-zero otherwise
737  */
738 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
739                           struct iattr *lower_ia)
740 {
741         int rc = 0;
742         struct inode *inode = dentry->d_inode;
743         struct ecryptfs_crypt_stat *crypt_stat;
744         loff_t i_size = i_size_read(inode);
745         loff_t lower_size_before_truncate;
746         loff_t lower_size_after_truncate;
747
748         if (unlikely((ia->ia_size == i_size))) {
749                 lower_ia->ia_valid &= ~ATTR_SIZE;
750                 return 0;
751         }
752         rc = ecryptfs_get_lower_file(dentry, inode);
753         if (rc)
754                 return rc;
755         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
756         /* Switch on growing or shrinking file */
757         if (ia->ia_size > i_size) {
758                 char zero[] = { 0x00 };
759
760                 lower_ia->ia_valid &= ~ATTR_SIZE;
761                 /* Write a single 0 at the last position of the file;
762                  * this triggers code that will fill in 0's throughout
763                  * the intermediate portion of the previous end of the
764                  * file and the new and of the file */
765                 rc = ecryptfs_write(inode, zero,
766                                     (ia->ia_size - 1), 1);
767         } else { /* ia->ia_size < i_size_read(inode) */
768                 /* We're chopping off all the pages down to the page
769                  * in which ia->ia_size is located. Fill in the end of
770                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
771                  * PAGE_CACHE_SIZE with zeros. */
772                 size_t num_zeros = (PAGE_CACHE_SIZE
773                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
774
775                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
776                         truncate_setsize(inode, ia->ia_size);
777                         lower_ia->ia_size = ia->ia_size;
778                         lower_ia->ia_valid |= ATTR_SIZE;
779                         goto out;
780                 }
781                 if (num_zeros) {
782                         char *zeros_virt;
783
784                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
785                         if (!zeros_virt) {
786                                 rc = -ENOMEM;
787                                 goto out;
788                         }
789                         rc = ecryptfs_write(inode, zeros_virt,
790                                             ia->ia_size, num_zeros);
791                         kfree(zeros_virt);
792                         if (rc) {
793                                 printk(KERN_ERR "Error attempting to zero out "
794                                        "the remainder of the end page on "
795                                        "reducing truncate; rc = [%d]\n", rc);
796                                 goto out;
797                         }
798                 }
799                 truncate_setsize(inode, ia->ia_size);
800                 rc = ecryptfs_write_inode_size_to_metadata(inode);
801                 if (rc) {
802                         printk(KERN_ERR "Problem with "
803                                "ecryptfs_write_inode_size_to_metadata; "
804                                "rc = [%d]\n", rc);
805                         goto out;
806                 }
807                 /* We are reducing the size of the ecryptfs file, and need to
808                  * know if we need to reduce the size of the lower file. */
809                 lower_size_before_truncate =
810                     upper_size_to_lower_size(crypt_stat, i_size);
811                 lower_size_after_truncate =
812                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
813                 if (lower_size_after_truncate < lower_size_before_truncate) {
814                         lower_ia->ia_size = lower_size_after_truncate;
815                         lower_ia->ia_valid |= ATTR_SIZE;
816                 } else
817                         lower_ia->ia_valid &= ~ATTR_SIZE;
818         }
819 out:
820         ecryptfs_put_lower_file(inode);
821         return rc;
822 }
823
824 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
825 {
826         struct ecryptfs_crypt_stat *crypt_stat;
827         loff_t lower_oldsize, lower_newsize;
828
829         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
830         lower_oldsize = upper_size_to_lower_size(crypt_stat,
831                                                  i_size_read(inode));
832         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
833         if (lower_newsize > lower_oldsize) {
834                 /*
835                  * The eCryptfs inode and the new *lower* size are mixed here
836                  * because we may not have the lower i_mutex held and/or it may
837                  * not be appropriate to call inode_newsize_ok() with inodes
838                  * from other filesystems.
839                  */
840                 return inode_newsize_ok(inode, lower_newsize);
841         }
842
843         return 0;
844 }
845
846 /**
847  * ecryptfs_truncate
848  * @dentry: The ecryptfs layer dentry
849  * @new_length: The length to expand the file to
850  *
851  * Simple function that handles the truncation of an eCryptfs inode and
852  * its corresponding lower inode.
853  *
854  * Returns zero on success; non-zero otherwise
855  */
856 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
857 {
858         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
859         struct iattr lower_ia = { .ia_valid = 0 };
860         int rc;
861
862         rc = ecryptfs_inode_newsize_ok(dentry->d_inode, new_length);
863         if (rc)
864                 return rc;
865
866         rc = truncate_upper(dentry, &ia, &lower_ia);
867         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
868                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
869
870                 mutex_lock(&lower_dentry->d_inode->i_mutex);
871                 rc = notify_change(lower_dentry, &lower_ia, NULL);
872                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
873         }
874         return rc;
875 }
876
877 static int
878 ecryptfs_permission(struct inode *inode, int mask)
879 {
880         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
881 }
882
883 /**
884  * ecryptfs_setattr
885  * @dentry: dentry handle to the inode to modify
886  * @ia: Structure with flags of what to change and values
887  *
888  * Updates the metadata of an inode. If the update is to the size
889  * i.e. truncation, then ecryptfs_truncate will handle the size modification
890  * of both the ecryptfs inode and the lower inode.
891  *
892  * All other metadata changes will be passed right to the lower filesystem,
893  * and we will just update our inode to look like the lower.
894  */
895 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
896 {
897         int rc = 0;
898         struct dentry *lower_dentry;
899         struct iattr lower_ia;
900         struct inode *inode;
901         struct inode *lower_inode;
902         struct ecryptfs_crypt_stat *crypt_stat;
903
904         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
905         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
906                 ecryptfs_init_crypt_stat(crypt_stat);
907         inode = dentry->d_inode;
908         lower_inode = ecryptfs_inode_to_lower(inode);
909         lower_dentry = ecryptfs_dentry_to_lower(dentry);
910         mutex_lock(&crypt_stat->cs_mutex);
911         if (S_ISDIR(dentry->d_inode->i_mode))
912                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
913         else if (S_ISREG(dentry->d_inode->i_mode)
914                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
915                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
916                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
917
918                 mount_crypt_stat = &ecryptfs_superblock_to_private(
919                         dentry->d_sb)->mount_crypt_stat;
920                 rc = ecryptfs_get_lower_file(dentry, inode);
921                 if (rc) {
922                         mutex_unlock(&crypt_stat->cs_mutex);
923                         goto out;
924                 }
925                 rc = ecryptfs_read_metadata(dentry);
926                 ecryptfs_put_lower_file(inode);
927                 if (rc) {
928                         if (!(mount_crypt_stat->flags
929                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
930                                 rc = -EIO;
931                                 printk(KERN_WARNING "Either the lower file "
932                                        "is not in a valid eCryptfs format, "
933                                        "or the key could not be retrieved. "
934                                        "Plaintext passthrough mode is not "
935                                        "enabled; returning -EIO\n");
936                                 mutex_unlock(&crypt_stat->cs_mutex);
937                                 goto out;
938                         }
939                         rc = 0;
940                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
941                                                | ECRYPTFS_ENCRYPTED);
942                 }
943         }
944         mutex_unlock(&crypt_stat->cs_mutex);
945
946         rc = inode_change_ok(inode, ia);
947         if (rc)
948                 goto out;
949         if (ia->ia_valid & ATTR_SIZE) {
950                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
951                 if (rc)
952                         goto out;
953         }
954
955         memcpy(&lower_ia, ia, sizeof(lower_ia));
956         if (ia->ia_valid & ATTR_FILE)
957                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
958         if (ia->ia_valid & ATTR_SIZE) {
959                 rc = truncate_upper(dentry, ia, &lower_ia);
960                 if (rc < 0)
961                         goto out;
962         }
963
964         /*
965          * mode change is for clearing setuid/setgid bits. Allow lower fs
966          * to interpret this in its own way.
967          */
968         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
969                 lower_ia.ia_valid &= ~ATTR_MODE;
970
971         mutex_lock(&lower_dentry->d_inode->i_mutex);
972         rc = notify_change(lower_dentry, &lower_ia, NULL);
973         mutex_unlock(&lower_dentry->d_inode->i_mutex);
974 out:
975         fsstack_copy_attr_all(inode, lower_inode);
976         return rc;
977 }
978
979 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
980                                  struct kstat *stat)
981 {
982         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
983         int rc = 0;
984
985         mount_crypt_stat = &ecryptfs_superblock_to_private(
986                                                 dentry->d_sb)->mount_crypt_stat;
987         generic_fillattr(dentry->d_inode, stat);
988         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
989                 char *target;
990                 size_t targetsiz;
991
992                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
993                 if (!IS_ERR(target)) {
994                         kfree(target);
995                         stat->size = targetsiz;
996                 } else {
997                         rc = PTR_ERR(target);
998                 }
999         }
1000         return rc;
1001 }
1002
1003 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1004                             struct kstat *stat)
1005 {
1006         struct kstat lower_stat;
1007         int rc;
1008
1009         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
1010         if (!rc) {
1011                 fsstack_copy_attr_all(dentry->d_inode,
1012                                       ecryptfs_inode_to_lower(dentry->d_inode));
1013                 generic_fillattr(dentry->d_inode, stat);
1014                 stat->blocks = lower_stat.blocks;
1015         }
1016         return rc;
1017 }
1018
1019 int
1020 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1021                   size_t size, int flags)
1022 {
1023         int rc = 0;
1024         struct dentry *lower_dentry;
1025
1026         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1027         if (!lower_dentry->d_inode->i_op->setxattr) {
1028                 rc = -EOPNOTSUPP;
1029                 goto out;
1030         }
1031
1032         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1033         if (!rc && dentry->d_inode)
1034                 fsstack_copy_attr_all(dentry->d_inode, lower_dentry->d_inode);
1035 out:
1036         return rc;
1037 }
1038
1039 ssize_t
1040 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1041                         void *value, size_t size)
1042 {
1043         int rc = 0;
1044
1045         if (!lower_dentry->d_inode->i_op->getxattr) {
1046                 rc = -EOPNOTSUPP;
1047                 goto out;
1048         }
1049         mutex_lock(&lower_dentry->d_inode->i_mutex);
1050         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1051                                                    size);
1052         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1053 out:
1054         return rc;
1055 }
1056
1057 static ssize_t
1058 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1059                   size_t size)
1060 {
1061         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1062                                        value, size);
1063 }
1064
1065 static ssize_t
1066 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1067 {
1068         int rc = 0;
1069         struct dentry *lower_dentry;
1070
1071         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1072         if (!lower_dentry->d_inode->i_op->listxattr) {
1073                 rc = -EOPNOTSUPP;
1074                 goto out;
1075         }
1076         mutex_lock(&lower_dentry->d_inode->i_mutex);
1077         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1078         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1079 out:
1080         return rc;
1081 }
1082
1083 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1084 {
1085         int rc = 0;
1086         struct dentry *lower_dentry;
1087
1088         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1089         if (!lower_dentry->d_inode->i_op->removexattr) {
1090                 rc = -EOPNOTSUPP;
1091                 goto out;
1092         }
1093         mutex_lock(&lower_dentry->d_inode->i_mutex);
1094         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1095         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1096 out:
1097         return rc;
1098 }
1099
1100 const struct inode_operations ecryptfs_symlink_iops = {
1101         .readlink = generic_readlink,
1102         .follow_link = ecryptfs_follow_link,
1103         .put_link = kfree_put_link,
1104         .permission = ecryptfs_permission,
1105         .setattr = ecryptfs_setattr,
1106         .getattr = ecryptfs_getattr_link,
1107         .setxattr = ecryptfs_setxattr,
1108         .getxattr = ecryptfs_getxattr,
1109         .listxattr = ecryptfs_listxattr,
1110         .removexattr = ecryptfs_removexattr
1111 };
1112
1113 const struct inode_operations ecryptfs_dir_iops = {
1114         .create = ecryptfs_create,
1115         .lookup = ecryptfs_lookup,
1116         .link = ecryptfs_link,
1117         .unlink = ecryptfs_unlink,
1118         .symlink = ecryptfs_symlink,
1119         .mkdir = ecryptfs_mkdir,
1120         .rmdir = ecryptfs_rmdir,
1121         .mknod = ecryptfs_mknod,
1122         .rename = ecryptfs_rename,
1123         .permission = ecryptfs_permission,
1124         .setattr = ecryptfs_setattr,
1125         .setxattr = ecryptfs_setxattr,
1126         .getxattr = ecryptfs_getxattr,
1127         .listxattr = ecryptfs_listxattr,
1128         .removexattr = ecryptfs_removexattr
1129 };
1130
1131 const struct inode_operations ecryptfs_main_iops = {
1132         .permission = ecryptfs_permission,
1133         .setattr = ecryptfs_setattr,
1134         .getattr = ecryptfs_getattr,
1135         .setxattr = ecryptfs_setxattr,
1136         .getxattr = ecryptfs_getxattr,
1137         .listxattr = ecryptfs_listxattr,
1138         .removexattr = ecryptfs_removexattr
1139 };